Well drilling bit



Sept. 12, 1967 M. E. WHITE WELL DRILLING BIT Filed Aug. 16, 1965 FIG. 3.

FIG. 4.

F G, 5 MARVIN E. WHITE INVENTOR.

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ATTORNEY United States Patent 3,340,940 WELL DRILLING BIT Marvin E. White, Fort Worth, Tex., assignor of forty-nine percent to John G. Elstrand, Fort Worth, Tex. Filed Aug. 16, 1965, Ser. No. 480,079 5 Claims. (Cl. 175+-412) This invention relates to a well drilling bit, and it concerns more particularly a bit for drilling comparatively shallow, small diameter holes, commonly referred to as shot holes, for use in geophysical exploration operations in which explosive charges are placed in such holes and detonated from the surface, and the resulting earth vibrations are recorded by seismograp-h.

In my copending application, Ser. No. 474,098, filed July 22, 1965, I have described and claimed certain specific improvements in a bit as hereinafter described which has heretofore been employed for the purpose contemplated by the invention.

The improvements described in my copending application above mentioned are applicable to a bit for use as described having a plurality of three circumferentially spaced removable blades which are received in longitudi-v nal channels therefor in thickened peripheral portions of a tubular blade holder having an externally threaded shank portion for engagement with the lower end of a drill pipe. Each of the blades has a short circumferentially extending portion extending laterally outwardly fro-m at least one side thereof, adjacent the upper end of the blade, which fits around the threaded shank portion of the blade holder and overlies a discontinuous upwardly facing external shoulder'on the blade holder communicating with the upper ends of the longitudinal channels therein. Said upper end portion of the blade is externally beveled for clamping engagement by a ring loosely surrounding the shank portion of the blade holder, in opposing relation to the lower end of the drill pipe and said shoulder. Said ring is internally beveled on its under side, whereby a downward thrust is applied to the blades relative to the blade holder as the blade holder is advanced relative to the drill pipe, upon tightening the threads thereof, and the blades are rigidly and removably clamped to the blade holder by abutting engagement of their mutually opposing surfaces.

The invention shown in my said copending application contemplates certain improvements and refinements of the mutually opposing surfaces on the blade holder and the blades, respectively, whereby the blades are clamped to the blade holder, between the blade holder and said ring, whereby the blades are positively secured against displacement in any direction relative to the blade holder and the structure is additionally reinforced so that the bit is characterized by its ruggedness and dependability in use as well as more efiicient. The strength of the bit is comparable to that of the drill pipe to which it is connected, and breakage of parts, as well as costly fishing jobs to recover parts lost in the hole, are substantially avoided by use of the invention.

The invention described in said copending application also contemplates certain improvements in the cutting surfaces of the blades whereby the blades are less subject to wear and their useful life is increased, while at the same time the rate at which the bit penetrates a formation being drilled is increased.

This invention concerns a completely new bit structure which is generally similar to the arrangement above described but in which the parts are substantially reversed.

According to the invention the end portion of the blade holder opposite its shank portion, which is square in transverse section, is received between a pair of channel shaped blade units, which are interchange-able with each other and each of which embraces substantially one-half of said square end portion of the blade holder. Each of said blade units has a pair of integral blades extending radially outwardly from two adjacent sides thereof, in circumferentially spaced relation to each other.

The upper end portions of the blade units, which are arcuate, are externally beveled for clamping engagement by a ring which loosely surrounds the shank portion of the blade holder, in opposing relation to the lower end of the drill pipe and the upper ends of the respective blade'units. Said ring is internally beveled on its under side, whereby a downward thrust is applied to the blade units relative to the blade holder as the blade holder is advanced rel-ative to the drill pipe, upon tightening the threads thereof, and the blade units are rigidly and removably clamped to the blade holder by abutting engagement of their Inutually opposing surfaces as hereinafter described.

The side flanges of the channel shaped blade units have downwardly and radially inwardly inclined surfaces on their lower ends for abutting engagement with correspondingly beveled lugs on opposite sides of the square end portion of the blade holder whereby the blade units are secured against longitudinal displacement in a downward direction relative to the blade holder, and are further secured against spreading in a radially outward direction relative thereto.

The invention will be readily understood by referring to the following description and the accompanying drawing, in which:

FIG. 1 is a side elevational View of a well drilling bit embodying the invention showing the two blade units in place, in opposing relation to each other, whereby the square end portion of the blade holder is substantially enclosed, showing the blade holder connected by its threaded shank portion to an adjoining section of drill pipe, shown fragmentarily, and showing the ring surrounding said threaded shank portion of the blade holder, in opposing relation to the lower end of the drill pipe and the beveled, arcuate upper end portions of the blade units;

FIG. 2 is :a bottom plan view of the bit as illustrated in FIG. 1;

FIG. 3 is a perspective view showing the blade holder in its detached position, with the blade units removed, as seen from the top and two adjacent sides thereof, showing the beveled ring, partly broken away, loosely surrounding the shank portion of the blade holder;

FIG. 4 is a perspective view showing one of the blade units in its detached position, as seen from the top and inner side thereof, facing radially outwardly relative to the assembled position of the blade unit; and

FIG. 5 is a transverse sectional view taken on the line 55 of FIG. 1.

Referring to FIGS. 1 and 2 of the drawings, the numeral 1 designates generally a well drilling bit having the invention incorporated therein, and the numeral 2 indicates the lower end portion of a drill pipe, shown fragmentarily, having the bit 1 connected thereto.

The bit 1 includes a tubular blade holder, shown best in FIG. 3 and indicated generally by the numeral 3, which has an upwardly extending externally threaded shank portion 4. The end portion of the blade holder 3 opposite its shank portion 4 is square in transverse section, as at 5;

The square end portion 5 of the tubular blade holder 3 is received between a pair of channel shaped blade units, indicated generally by the numerals 6, which are comprising the bottom 9 and one of the side flanges 10 of the respective channel shaped blade units 6.

The side flanges 10 are substantially one-half as wide as the bottom 9 of the channel shaped blade units 6, and the blades 7, 8 are positioned on the trailing sides of the bottoms 9 and on the trailing side flanges 10 of the blade units 6, respectively, relative to the direction of rotation of the bit 1.

The integral blades 7, 8 are substantially planar, and the position of the blades 7, 8 relative to the sides 9, 10 of the blade units 6 is such that the leading sides 11, 12 of the blades 7, 8, relative to the direction of rotation of the bit 1, lie in planes which are perpendicular to the longitudinal axis of the bit 1.

The upper end portions of the blade units 6, which are arcuate, are externally beveled as at 13 for clamping engagement by a ring 14 which loosely surrounds the shank portion 4 of the blade holder 3, in opposing relation to the lower end of the drill pipe 2 and the upper ends of the blade units 6.

The ring 14 is internally beveled on its under side, as at 15, whereby a downward thrust is applied to the blade units 6 relative to the blade holder 3 as the blade holder 3 is advanced relative to the drill pipe 2, upon tightening the threads thereof, and the blade units 6 are rigidly and removably clamped to the blade holder 3 by abutting engagement of their mutually opposing surfaces as hereinafter described.

The side flanges 10 of the channel shaped blade units 6 have downwardly and radially inwardly inclined surfaces on their lower ends, as at 16, for abutting engagement with correspondingly beveled lugs 17 on opposite sides of the square end portion of the blade holder 3 whereby the blade units 6 are secured against longitudinal displacement in a downward direction relative to the blade holder 3, and are further secured against displacement in a radially outward direction relative thereto, whereby the blade units 6 are spread apart.

The outer longitudinal edges of the blades 7, 8 are straight for a major portion of their lengths, as at 18, 19. The lower end portions of the blades 7, 8, indicated by the numerals 20, 21, extend downwardly and radially inwardly below the blade holder 3, and the width of the blades 7, 8 is progressively reduced by steps immediately adjacent the lower ends 20, 21 thereof. The lower end portions 20 of the blades 7, which extend downwardly and radially inwardly farther than the lower end portions 21 of the blades 8, terminate near the middle of the bit 1 and are pointed at their extreme lower ends. Hard metal inserts 22, 23 are applied to the leading sides 11, 12 of the blades 7, 8, relative to the direction of rotation of the bit 1, adjacent the lower ends 20, 21 thereof.

The blades 7, 8 of the respective blade units 6 are offset circumferentially relative to the corresponding blades 7, 8 of the opposite blade units 6, as shown! best in FIG. 2.

The invention may be modified in various ways without departing from the spirit and scope thereof.

I claim:

1. In a well drilling bit having replaceable blade units, the combination of a tubular blade holder having an externally threaded shank portion for engagement with a drill pipe, said blade holder being square in transverse section for a major portion of its length beginning at the end thereof opposite said shank portion, a pair of channel shaped blade units each embracing substantially onehalf of said square end portion of said blade holder and together substantially enclosing it, each of said blade units having a pair of integral blades extending radially outwardly from two adjacent sides thereof, in circumferentially spaced relation to each other, and means removably clamping said blade units to said blade holder.

2. The structure of claim 1, said blade units having arcuate, externally beveled upper end portions, a ring loosely surrounding said shank portion of said blade holder, for abutting engagement with the adjacent end of said drill pipe, said ring being internally beveled on its under side for abutting engagement with said upper end portions of said blade units, and mutually opposing surfaces on said blade units and said blade holder below said ring coacting with said ring, upon tightening the threads whereby said blade holder is connected to said drill pipe, whereby said blade units are removably clamped between said blade holder and said ring.

3. The structure of claim 2, the side flanges of said blade units having downwardly and radially inwardly inclined surfaces on their lower ends and said blade holder having correspondingly beveled lugs on opposite sides of said square end portion immediately adjacent its lower end for abutting engagement with said lower ends of said side flanges of said blade units whereby said blade units are secured against longitudinal displacement in a downward direction relative to the blade holder, and are further secured against displacement in a radially outward direction relative thereto, whereby said blade units are prevented from being spread apart.

4. The structure of claim 1, said two adjacent sides of said blade units comprising the bottom and one of the side flanges of the respective blade units, said side flanges being substantially one-half as wide as said bottom of said blade units, and said blades being positioned on the trailing sides of the bottom and on the trailing side flanges of the respective blade units, relative to the direction of rotation of the bit, said blades being substantially planar and the positions of said blades relative to said sides of said blade units being such that the leading sides of said blades, relative to the direction of rotation of the bit, lie in planes which are perpendicular to the longitudinal axis of the bit.

5. The structure of claim 4, the outer longitudinal edges of said blades being straight for a major portion of their lengths, and the lower end portions of said blades extending downwardly and radially inwardly below said blade holder, the width of said blades being progressively reduced by steps immediately adjacent their lower ends, and the lower end portions of one of the blades of one of said blade units and the corresponding blade of the opposite blade unit extending downwardly and radially inwardly farther than the lower end portions of the other of the blades of the respective blade units and terminating near the middle of the bit, and being pointed at their extreme lower ends.

References Cited UNITED STATES PATENTS 1,426,681 8/1922 Smith et al. 175-412 X 2,446,795 8/ 1948 Trimble 175-4l2 2,498,251 2/1950 Creel t 1754l2 2,861,779 11/1958 White l4l2 CHARLES E. OOONNELL, Primary Examiner.

NILE C. BYERS, JR., Assistant Examiner. 

1. IN A WELL DRILLING BIT HAVING REPLACEABLE BLADE UNITS, THE COMBINATION OF A TUBULAR BLADE HOLDER HAVING AN EXTERNALLY THREADED SHANK PORTION FOR ENGAGEMENT WITH A DRILL PIPE, SAID BLADE HOLDER BEING SQUARE IN TRANSVERSE SECTION FOR A MAJOR PORTION OF ITS LENGTH BEGINNING AT THE END THEREOF OPPOSITE SAID SHANK PORTION, A PAIR OF CHANNEL SHAPED BLADE UNITS EACH EMBRACING SUBSTANTIALLY ONEHALF OF SAID SQUARE END PORTION OF SAID BLADE HOLDER AND TOGETHER SUBSTANTIALLY ENCLOSING IT, EACH OF SAID BLADE UNITS HAVING A PAIR OF INTEGRAL BLADES EXTENDING RADIALLY OUTWARDLY FROM TWO ADJACENT SIDES THEREOF, IN CIRCUMFERENTIALLY SPACED RELATION TO EACH OTHER, AND MEANS REMOVABLY CLAMPING SAID BLADE UNITS TO SAID BLADE HOLDER. 